'''
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License") you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 * <p>
 * http://www.apache.org/licenses/LICENSE-2.0
 * <p>
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
'''


#import org.apache.jena.base.module.Subsystem
#import org.apache.jena.base.module.SubsystemRegistry
#import org.apache.jena.base.module.SubsystemRegistryServiceLoader

'''
 Jena "system" - simple controls for ensuring components are loaded and initialized.
 * <p>
 * All initialization should be concurrent and thread-safe.  In particular,
 * some subsystems need initialization in some sort of order (e.g. ARQ before TDB).
 * <p>
 * This is achieved by "levels": levels less than 500 are considered "Jena system levels"
 * and are reserved.
 * <ul>
 * <li>0 - reserved
 * <li>10 - jena-core
 * <li>20 - RIOT
 * <li>30 - ARQ
 * <li>40 - TDB
 * <li>50-100 - Other Jena system modules.
 * <li>101 - Fuseki
 * <li>102-9998 - Application
 * <li>9999 - other
 * </ul>
 * See also the <a href="http://jena.apache.org/documentation/notes/system-initialization.html">notes on Jena initialization</a>.
'''

DEBUG_INIT = False
initialized = False

class JenaSystem:

    # private static Subsystem<JenaSubsystemLifecycle> 
    singleton = None

    # Don't rely on class initialization.
    @staticmethod
    def setup():
        pass
        # Called inside synchronized
        #if (singleton == null):
            # singleton = new Subsystem<>(JenaSubsystemLifecycle.class)
            # SubsystemRegistry<JenaSubsystemLifecycle> reg =
            #         new SubsystemRegistryServiceLoader<>(JenaSubsystemLifecycle.class)
            # singleton.setSubsystemRegistry(reg)
            # reg.add(new JenaInitLevel0())
        

    def __init__(self):
        pass

    '''
     * Development support - flag to enable output during
     * initialization. Output to:@code System.err, not a logger
     * to avoid the risk of recursive initialization.
    '''
    # public static boolean DEBUG_INIT = false
    # private static volatile boolean initialized = false

    ''' Output a debugging message if DEBUG_INIT is set'''
    # public static void logLifecycle(String fmt, Object... args):
    #     if (!DEBUG_INIT)
    #         return
    #     System.err.printf(fmt, args)
    #     System.err.println()

    @staticmethod
    def init():
        pass
        # if (initialized)
        #     return
        # synchronized (JenaSystem.class):
        #     if (initialized)
        #         return
        #     initialized = true
        #     setup()
        #     if (DEBUG_INIT)
        #         singleton.debug(DEBUG_INIT)
        #     singleton.initialize()
        #     singleton.debug(false)
        
    
    @staticmethod
    def shutdown():
        pass
        # singleton.shutdown()
    

    ''' The level 0 subsystem - inserted without using the Registry load function.
     *  There should be only one such level 0 handler.
    '''
    # private static class JenaInitLevel0 implements JenaSubsystemLifecycle:
    #     @Override
    #     public void start():
    #         logLifecycle("Jena initialization")
    #
    #
    #     @Override
    #     public void stop():
    #         logLifecycle("Jena shutdown")
    #
    #
    #     @Override
    #     public int level():
    #         return 0
        
    

